Replace Toilet Fill Valve

Replace the toilet fill valve by shutting off the water, draining the tank, removing the old valve, installing and adjusting the new one, then restoring water and checking carefully for leaks and proper refill level.

Easy · 30-60 minutes

Tools

  • Adjustable wrench
  • Small sponge or towel
  • Bucket
  • Channel-lock pliers

Materials

  • Replacement toilet fill valve
  • New shank washer and locknut (usually included with the valve)
  • Flexible supply line (only if the existing one is old or leaking)

Safety

  • Turn off the toilet supply valve before disconnecting the water line.
  • Flush the toilet and remove as much water from the tank as possible before loosening parts.
  • Place a towel or bucket under the supply connection to catch remaining water.
  • Do not overtighten plastic nuts or the tank can crack or the valve can deform.
  • Turn the water back on slowly and inspect all connections for leaks.
  • Stop and call a professional if the shutoff valve will not close fully or if the tank or supply connection is damaged.

Steps

  1. Step 1: Shut off the water and empty the tank

    • Turn the toilet supply valve clockwise until it stops.
    • Flush the toilet and hold the handle down to drain as much water from the tank as possible.
    • Use a sponge or towel to soak up the remaining water in the bottom of the tank.
    • Place a bucket or towel under the supply line connection below the tank.

    Check: The tank is mostly empty. · No more water is entering the tank. · The area under the tank is protected from drips.

  2. Step 2: Disconnect the supply line and remove the old fill valve

    • Unscrew the water supply line from the bottom of the fill valve shank under the tank.
    • Inside the tank, disconnect the small refill tube from the overflow tube.
    • Loosen and remove the plastic locknut holding the fill valve to the tank.
    • Lift the old fill valve out from inside the tank.

    Check: The old fill valve is fully removed. · The supply line connection and tank opening are clean and accessible. · No old rubber pieces or debris are left around the mounting hole.

  3. Step 3: Prepare the new fill valve

    • Adjust the height of the new fill valve according to the manufacturer's instructions before installing it.
    • Set the top of the valve so it will sit above the overflow tube and within the tank height limits specified by the manufacturer.
    • Make sure the rubber shank washer is installed in the correct position on the new valve.

    Check: The new valve height matches the tank size. · The washer is installed correctly on the valve. · The valve can sit straight in the tank without interference.

  4. Step 4: Install the new fill valve

    • Insert the new fill valve through the mounting hole in the bottom of the tank.
    • Hold the valve upright and position the refill outlet toward the overflow tube.
    • Thread the locknut onto the valve shank from underneath the tank and tighten it snugly by hand, then slightly more with pliers if needed.
    • Do not overtighten.

    Check: The fill valve is upright and stable. · The locknut is snug but not excessively tight. · The valve does not wobble noticeably.

  5. Step 5: Reconnect the refill tube and water supply

    • Attach the refill tube from the fill valve to the overflow tube using the provided clip.
    • Make sure the refill tube discharges into the overflow tube without being pushed down inside it.
    • Reconnect the water supply line to the bottom of the fill valve shank.
    • Tighten the supply connection snugly without overtightening.

    Check: The refill tube is clipped securely to the overflow tube. · The refill tube is not inserted down into the overflow pipe. · The supply line connection is snug and aligned straight.

  6. Step 6: Turn the water on and adjust the water level

    • Slowly open the supply valve and let the tank refill.
    • Watch the fill valve and supply connection closely for leaks.
    • Adjust the fill level using the valve adjustment screw or clip so the water stops at the marked water line in the tank or about 1 inch below the top of the overflow tube.
    • Flush the toilet and observe the refill cycle.

    Check: There are no leaks at the supply line, locknut, or tank opening. · The water shuts off cleanly at the correct level. · The bowl refills properly after flushing.

  7. Step 7: Test and clean up

    • Flush the toilet several times to confirm consistent operation.
    • Recheck all connections underneath and around the tank for slow drips.
    • Wipe the area dry and remove tools and towels.
    • Dispose of the old fill valve.

    Check: The toilet refills normally on repeated flushes. · No slow leaks appear after several minutes. · The work area is dry and clean.

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Replace Toilet Fill Valve0 of 7 steps done

Written by AI, not checked by a tradesperson. How this works

Step-by-Step Instructions

Step 1 of 7

Shut off the water and empty the tank

Diagram for step 1: Shut off the water and empty the tank
Fig. 1Shut off the water and empty the tank
  • Turn the toilet supply valve clockwise until it stops.
  • Flush the toilet and hold the handle down to drain as much water from the tank as possible.
  • Use a sponge or towel to soak up the remaining water in the bottom of the tank.
  • Place a bucket or towel under the supply line connection below the tank.
Check

The tank is mostly empty. • No more water is entering the tank. • The area under the tank is protected from drips.

Was this step clear?
Step 2 of 7

Disconnect the supply line and remove the old fill valve

Diagram for step 2: Disconnect the supply line and remove the old fill valve
Fig. 2Disconnect the supply line and remove the old fill valve
  • Unscrew the water supply line from the bottom of the fill valve shank under the tank.
  • Inside the tank, disconnect the small refill tube from the overflow tube.
  • Loosen and remove the plastic locknut holding the fill valve to the tank.
  • Lift the old fill valve out from inside the tank.
Check

The old fill valve is fully removed. • The supply line connection and tank opening are clean and accessible. • No old rubber pieces or debris are left around the mounting hole.

Was this step clear?
Step 3 of 7

Prepare the new fill valve

Diagram for step 3: Prepare the new fill valve
Fig. 3Prepare the new fill valve
  • Adjust the height of the new fill valve according to the manufacturer's instructions before installing it.
  • Set the top of the valve so it will sit above the overflow tube and within the tank height limits specified by the manufacturer.
  • Make sure the rubber shank washer is installed in the correct position on the new valve.
Check

The new valve height matches the tank size. • The washer is installed correctly on the valve. • The valve can sit straight in the tank without interference.

Was this step clear?
Step 4 of 7

Install the new fill valve

Diagram for step 4: Install the new fill valve
Fig. 4Install the new fill valve
  • Insert the new fill valve through the mounting hole in the bottom of the tank.
  • Hold the valve upright and position the refill outlet toward the overflow tube.
  • Thread the locknut onto the valve shank from underneath the tank and tighten it snugly by hand, then slightly more with pliers if needed.
  • Do not overtighten.
Check

The fill valve is upright and stable. • The locknut is snug but not excessively tight. • The valve does not wobble noticeably.

Was this step clear?
Step 5 of 7

Reconnect the refill tube and water supply

Diagram for step 5: Reconnect the refill tube and water supply
Fig. 5Reconnect the refill tube and water supply
  • Attach the refill tube from the fill valve to the overflow tube using the provided clip.
  • Make sure the refill tube discharges into the overflow tube without being pushed down inside it.
  • Reconnect the water supply line to the bottom of the fill valve shank.
  • Tighten the supply connection snugly without overtightening.
Check

The refill tube is clipped securely to the overflow tube. • The refill tube is not inserted down into the overflow pipe. • The supply line connection is snug and aligned straight.

Was this step clear?
Step 6 of 7

Turn the water on and adjust the water level

Diagram for step 6: Turn the water on and adjust the water level
Fig. 6Turn the water on and adjust the water level
  • Slowly open the supply valve and let the tank refill.
  • Watch the fill valve and supply connection closely for leaks.
  • Adjust the fill level using the valve adjustment screw or clip so the water stops at the marked water line in the tank or about 1 inch below the top of the overflow tube.
  • Flush the toilet and observe the refill cycle.
Check

There are no leaks at the supply line, locknut, or tank opening. • The water shuts off cleanly at the correct level. • The bowl refills properly after flushing.

Was this step clear?
Step 7 of 7

Test and clean up

Diagram for step 7: Test and clean up
Fig. 7Test and clean up
  • Flush the toilet several times to confirm consistent operation.
  • Recheck all connections underneath and around the tank for slow drips.
  • Wipe the area dry and remove tools and towels.
  • Dispose of the old fill valve.
Check

The toilet refills normally on repeated flushes. • No slow leaks appear after several minutes. • The work area is dry and clean.

Was this step clear?

Common Mistakes

  • ×Forgetting to shut off the supply valve completely before disconnecting the line.
  • ×Leaving water in the tank and spilling it during removal.
  • ×Installing the new valve at the wrong height.
  • ×Pushing the refill tube down inside the overflow tube, which can cause siphoning problems.
  • ×Overtightening the plastic locknut or supply connection.
  • ×Failing to check for slow leaks after the first refill and several test flushes.

When to Call a Professional

  • The shutoff valve does not fully stop the water.
  • The supply line fitting is corroded, seized, or begins to leak at the wall valve.
  • The tank is cracked or the mounting hole is damaged.
  • The new fill valve will not fit your toilet model or cannot be adjusted correctly.
  • The toilet still runs continuously after correct installation and adjustment.
  • You see persistent leaks that do not stop with proper reassembly.

Notes

  • Many replacement fill valves are universal, but confirm compatibility with your toilet before starting.
  • If the existing supply line is old, stiff, or shows signs of rust or leakage, replacing it at the same time is a good preventive step.
  • Follow the specific height and water-level marks provided by the fill valve manufacturer if they differ slightly from general guidance.

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